Sugar degradation during autoclaving: Effects of duration and solution volume on breakdown of glucose

Wang, Xiao-Jia; Hsiao, Ke‐Cheng

doi:10.1111/j.1399-3054.1995.tb00947.x

Cited by 24 publications

(9 citation statements)

References 15 publications

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“…Autoclaving LB medium led to fluctuations in quantitative results; the numbers of persisters and nondividing cells at particular time points were difficult to reproduce. Several chemical conversions occur during the autoclaving of growth media (30,44), leading to changes in the growth-supporting properties of those media (11,31). The chemical effect of autoclaving depends on several factors, including the volume of material and type of autoclave (6,44), and this can decrease the reproducibility of results.…”

Section: Resultsmentioning

confidence: 99%

“…Several chemical conversions occur during the autoclaving of growth media (30,44), leading to changes in the growth-supporting properties of those media (11,31). The chemical effect of autoclaving depends on several factors, including the volume of material and type of autoclave (6,44), and this can decrease the reproducibility of results. These effects could be particularly relevant in very complex media, such as LB (29,37).…”

Section: Resultsmentioning

confidence: 99%

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Age of Inoculum Strongly Influences Persister Frequency and Can Mask Effects of Mutations Implicated in Altered Persistence

et al. 2011

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The majority of cells transferred from stationary-phase culture into fresh medium resume growth quickly, while a few remain in a nongrowing state for longer. These temporarily nonproliferating bacteria are tolerant of several bactericidal antibiotics and constitute a main source of persisters. Several genes have been shown to influence the frequency of persisters in Escherichia coli, although the exact mechanism underlying persister formation is unknown. This study demonstrates that the frequency of persisters is highly dependent on the age of the inoculum and the medium in which it has been grown. The hipA7 mutant had 1,000 times more persisters than the wild type when inocula were sampled from younger stationary-phase cultures. When started after a long stationary phase, the two displayed equal and elevated persister frequencies. The lower persister frequencies of glpD, dnaJ, and surA knockout strains were increased to the level of the wild type when inocula aged. The mqsR and phoU deletions showed decreased persister levels only when the inocula were from aged cultures, while sucB and ygfA deletions had decreased persister levels irrespective of the age of the inocula. A dependency on culture conditions underlines the notion that during screening for mutants with altered persister frequencies, the exact experimental details are of great importance. Unlike ampicillin and norfloxacin, which always leave a fraction of bacteria alive, amikacin killed all cells in the growth resumption experiment. It was concluded that the frequency of persisters depends on the conditions of inoculum cultivation, particularly its age, and the choice of antibiotic.Genetically homogeneous bacterial cultures can give rise to subpopulations with different physiological properties (38). This kind of heterogeneity can be demonstrated in terms of growth resumption when stationary-phase bacteria are diluted in fresh medium: some cells start growth immediately, some later, and some do not recover during the period of observation (2, 15, 33). Variation in recovery could reflect the random nature of cell damage (8). Alternatively, as rapidly recovering bacteria are more vulnerable to harmful environmental conditions than dormant ones, the wide range of growth resumption times could represent an ecological strategy (11,21,39). For example, the majority of bactericidal antibiotics kill growing bacteria, and nongrowing cells survive (41). Furthermore, antibiotic-sensitive growing cultures cannot be sterilized by bactericidal drugs, suggesting the existence of a small subpopulation of nongrowing bacteria (4). These bacteria, called persisters, can survive antibiotic treatment and resume growth after removal of the drug (23).Several mutations lead to increased or decreased persister levels (9,10,13,19,24,25,27,40). A classical mutant with increased persister frequency is the hipA7 strain (27), which carries mutations in the gene coding for the toxin in the HipAB toxin-antitoxin pair (21). This mutation decreases the affinity of the toxin for anti...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Age of Inoculum Strongly Influences Persister Frequency and Can Mask Effects of Mutations Implicated in Altered Persistence

et al. 2011

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“…The culture medium is commonly autoclaved (120 °C and 1 kgf cm -2 for 20-30 min) for in vitro plant cultivation, but this technique delays the culture medium preparation and increases the cost of micropropagated plantlets (CARDOSO, 2009;TEIXEIRA et al, 2008). The autoclaving could also result in production of toxic compounds for plant cultivation, such as 5-(hydroxymethyl)-2-furaldehyde and phenolics (WANG and HSIAO, 1995).…”

Section: Introductionmentioning

confidence: 99%

Easy and efficient chemical sterilization of the culture medium for in vitro growth of gerbera using chlorine dioxide (ClO2)

Cardoso¹,

Inthurn

2018

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Micropropagation techniques changed the production of clonal plantlets in the world. However, the high costs of micropropagated plantlets continue as the main constraint for the expansion of the technique. This paper aimed to test the use of the chemical sterilization of culture medium using chlorine dioxide (ClO2) for in vitro cultivation of gerbera. There was used gerbera in vitro shoots in the stage of rooting for these experiments, using 0.0035%, 0.0070% and 0.0105% of chlorine dioxide in the culture medium. Also, peracetic acid was tested previously for sterilization, but resulted in microbial contamination. Chemical sterilization of the culture medium was successfully using ClO2 at 0.0035% to 0.0105% (100% decontamination) at rooting and elongation stage of gerbera with production of plantlets with similar (number of leaves, total and root fresh weight) or higher quality (mainly aerial part) at rooting/elongation stage, compared with autoclaved culture medium. The increase of concentration of ClO2 also resulted in increasing of height and fresh weight of aerial part of gerberas. The ClO2 could replace the autoclaving with production of sterilized culture medium without phytotoxic problems to gerbera in vitro cultivation.

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“…On the one hand, the fact of finding glucose in the liquid fraction, even under conditions of smoother pretreatments, suggests that glucose could come from another source more easily soluble than cellulose. On the other hand, glucose could constitute an important sugar of the hemicellulosic component and could be released from this component [70]. In addition, the fact that the values are different under diverse operating conditions supports this hypothesis.…”

Section: Recovery Of Sugarsmentioning

confidence: 82%

“…However, in this case, some additional experimentation would be performed in order to analyze the degradation of these sugars under severe operating conditions. It is important to highlight that it is impossible to have zero sugar degradation at the analyzed operating temperatures when sugar release comes from soluble sugars (glucose and xylose) [70][71][72]. Xylose is especially sensitive.…”

Section: Recovery Of Sugarsmentioning

confidence: 99%

Liquid Hot Water Pretreatment and Enzymatic Hydrolysis as a Valorization Route of Italian Green Pepper Waste to Delivery Free Sugars

Martín-Lara

Chica-Redecillas

Pérez

et al. 2020

Foods

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In this work, liquid hot water pretreatment (autohydrolysis) was used to improve enzymatic hydrolysis of a commonly consumed vegetable waste in Spain, Italian green pepper, to finally produce fermentable sugars. Firstly, the effect of temperature and contact time on sugar recovery during pretreatment (in insoluble solid and liquid fraction) was studied in detail. Then, enzymatic hydrolysis using commercial cellulase was performed with the insoluble solid resulting from pretreatment. The objective was to compare results with and without pretreatment. The results showed that the pretreatment step was effective to facilitate the sugars release in enzymatic hydrolysis, increasing the global sugar yield. This was especially notable when pretreatment was carried out at 180 °C for 40 min for glucose yields. In these conditions a global glucose yield of 61.02% was obtained. In addition, very low concentrations of phenolic compounds (ranging from 69.12 to 82.24 mg/L) were found in the liquid fraction from enzymatic hydrolysis, decreasing the possibility of fermentation inhibition produced by these components. Results showed that Italian green pepper is an interesting feedstock to obtain free sugars and prevent the enormous quantity of this food waste discarded annually.

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Sugar degradation during autoclaving: Effects of duration and solution volume on breakdown of glucose

Cited by 24 publications

References 15 publications

Age of Inoculum Strongly Influences Persister Frequency and Can Mask Effects of Mutations Implicated in Altered Persistence

Age of Inoculum Strongly Influences Persister Frequency and Can Mask Effects of Mutations Implicated in Altered Persistence

Easy and efficient chemical sterilization of the culture medium for in vitro growth of gerbera using chlorine dioxide (ClO2)

Liquid Hot Water Pretreatment and Enzymatic Hydrolysis as a Valorization Route of Italian Green Pepper Waste to Delivery Free Sugars

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